(a) Field of the Invention
The present invention relates to an organic electroluminescence display using a metallocene compound, and more particularly to an organic electroluminescence display with a simple structure using a metallocene compound as a luminescent material.
(b) Description of the Related Art
The basic concept of an OELD (Organic Electro-Luminescence Display) is to obtain light energy from an organic luminescent material located between two electrodes to which an electric field is applied. Differently from an LCD, an OELD is an emissive display with a fast response, a wide view angle, and high contrast. Also, since it enables a flexible display that is thinner than 2 mm, it is emerging as a next-generation flat panel display (FPD).
Organic luminescent materials used for an OELD are classified as low molecular compounds and polymer compounds. A representative substance of the low molecular compounds is Al(HQ)3 (HQ is 8-hydroxyquinoline), a green-luminescent aluminum quinoline derivative developed by Kodak, and a representative substance of the polymer compounds is poly(p-phenylenevinylene) (PPV) developed by CDT (Cambridge Display Technology).
The low molecular organic EL devices have been developed actively since the mid-1980s, but development of the polymer organic EL devices is only at the initial state. While a low molecular organic EL device requires an electron/hole injection layer and a transport layer in addition to an emission layer, a polymer organic EL luminescent device can have a simple organic EL structure due to the inherent double bonding (π-bonding; resonance structure) of the polymer organic EL luminescent material. That is, the polymer organic EL material can be formed into a film between two electrodes using a spin coater or an ink jet to make an organic EL device easily.
Much research and development has been undertaken on conductive polymers having intramolecular π-electron resonance structures. Currently, PPV and its derivatives, poly(3-alkyl-thiophene) (PAT) and its derivatives, poly(9,9-dialkylfluorene) (PDAF), and so forth are known. These compounds are readily soluble in solvents and form thin films on a substrate. Additionally, any color, including blue, green, and red, can be obtained by selecting compounds with different side chains.
Accordingly, consistent research on polymer luminescent materials and their physical properties is required to develop an organic electroluminescence display with a simple structure.